Protecciones sobrecorriente circuitos baja tensión-Schneider

1. International standard
IEC 60947-2
Low voltage switchgear
Part 2: Circuit-breakers
DBTP83-Fr-03/99
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052387
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2. 2
EC 60947-2
Contents
n I. General 3
n 2. Definitions 8
n 3. Circuit-breaker characteristics 10
n 4. Constructional requirements 14
n 5. Specific points (appendices) 21
n 6. Tests 27
n 7. Conclusion 34

3. 3
EC 60947-2
Standard IEC 60947-2
n Came into force in 1989
n Takes into account the circuit-breaker main technological upgrades
Standard IEC 60947-2
n Is internationally recognized and approved
and is applied in the majority of countries (> 100)
General
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IEC
IEC
UL
CSA
IEC
JIS/IEC
IEC
IEC
IEC

4. 4
EC 60947-2
General
constitution
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IEC
60947
IEC
60947-1
IEC
60 947-2
IEC 60
947-3
IEC 60
947-4-1
IEC 60
947-4-2
IEC 60
947-6-2
IEC 60
947-7-1 … ...
or
or or or
or or
Standard IEC 60947-2 is part of a set of 7 standards characterizing
low voltage switchgear
General
rules
Circuit-breakers
Switches
Contactors
and starters
Dimmers
and starters
Control and
connection
devices
Terminal
block

5. 5
EC 60947-2
General
The scope
« Standard IEC 60947-2 applies to circuit-breakers, the main contacts
of which are intended to be connected to circuits, the rated voltage of
which does not in exceed 1000 V AC or 1500 DC; … »
The standard applies to circuit-breakers intended for use by
experienced operators.
035928a
041624
031107a

6. 6
EC 60947-2
General
The scope
Standard IEC 60947-2 contains additional specifications for:
n Circuit-breakers suitable for isolation
n Residual current devices (appendix B)
n Circuit-breakers with electronic protection (appendices J and F)
n Circuit-breakers for IT systems (appendix H)
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7. 7
EC 60947-2
General
Standard IEC 60947-2 defines
n The circuit-breaker classification
o according to utilization category A or B
o according to design type
air circuit-breaker, moulded case circuit-breaker
n The circuit-breaker mechanical and electrical data:
size, trip unit, etc.
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8. 8
EC 60947-2
Definitions
Circuit-breaker classification
Utilization category A Utilization category B
Circuit-breaker not specifically intended Circuit-breaker specifically intended
for discrimination for discrimination:
nWithout an intentional short-time delay nWith intentional short-time delay
(adjustable)
nWithout short time withstand current nWith short time withstand current
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9. 9
EC 60947-2
Extract from appendix K of standard IEC 60947-2
Characteristics Ue Rated operational voltage
voltage Ui Rated insulation voltage
Uimp Rated impulse withstand voltage
current In Rated current
Ith Conventional free-air thermal current
Ithe Conventional enclosed thermal current
Icm Rated short-circuit making capacity
short-circuit Icu Rated ultimate short-circuit breaking capacity
Ics Rated service short-circuit breaking capacity
Icw Rated short-time withstand current
Ir Adjustable overload setting current
1.05 x Ir Conventional non-tripping current
trip unit 1.30 x Ir Conventional tripping current
Isd Short time delay tripping setting current
Ii Instantaneous tripping setting current
Definitions
Terminology / Vocabulary

10. 10
EC 60947-2
Circuit-breaker characteristics
Overload withstand
In (in A rms) = rated current
n Maximum uninterrupted current
withstood at ambient
temperature, given without
abnormal temperature rise
Ir (in A rms) = adjustable
overload setting current
n Ir depends on In
n Ir characterizes the
overload protection
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11. 11
EC 60947-2
Circuit-breaker characteristics
Short-circuit withstand
Icu (kA rms) = rated ultimate
short-circuit breaking capacity
n This performance expresses
the maximum value of the
short-circuit current that can
be broken by the circuit-breaker
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12. 12
EC 60947-2
Circuit-breaker characteristics
Short-circuit withstand
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Standard IEC 60947-2 introduces a
new important performance
Ics (as a % of Icu) = rated service
short-circuit breaking capacity
n This performance expresses
the suitability of a circuit-breaker to
ensure fully normal service after
breaking this current 3 times
n Normal ratio between Ics and Icu
Utilization category A Utilization category B
% of Icu % of Icu
25
50 50
75 75
100 100

13. 13
EC 60947-2
Circuit-breaker characteristics
Short-circuit withstand
Standard IEC 60947-2 introduces a
new performance for
category B circuit-breakers
Icw (in kA rms) = rated short-time
withstand current
n Icw is the maximum short-circuit
current that a circuit-breaker can
withstand for a short duration
∆t without deterioration of
these characteristics
n ICW must be at least equal to
12 In or 5 kA for In ≤2500 A
30 kA for In > 2500 A
n The standardized delay time ∆t
is: 0.05 - 0.1 - 0.25 - 0.5 -
or 1s
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14. 14
EC 60947-2
Constructional requirements
Isolation co-ordination
The circuit-breaker, as a safety device, must be able to withstand
n Network overvoltages
this suitability is characterized by the withstand to the conventional
dielectric test at 2 Ui + 1000 - 1 min at power frequency
n Impulse voltages ( «lightning stroke» simulation)
this suitability is characterized by the withstand to the
1.2/ 50 µs impulse voltage test of value Uimp
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15. 15
EC 60947-2
Constructional requirements
Isolation co-ordination
Uimp (kV peak) = rated impulse withstand voltage
Characterization of Uimp
n Depends on the LV network voltage
n Depends on the position of the circuit-breaker in the LV network
n Depends on altitude: Uimp must be valid up to 2000 m
tests carried out at +23 % of value
8

16. 16
EC 60947-2
Characterization of Uimp
Nominal Applications
installation voltage
at the origin of the on the distribution and at load
installation/MSB final circuits level
230/400 V 6 4 2.5
400/690 V 8 6 4
Constructional requirements
Isolation co-ordination
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17. 17
EC 60947-2
Constructional requirements
Isolation co-ordination
Industrial circuit-breaker Uimp = 8 kV
n Tests to be considered
o Uimp + 23 % = 9.8 kV
o standard industrial circuit-breakers and those suitable for isolation
Application of Impulse voltage value
impulse voltage Breakers Disconnector Breakers
Phase-to-phase 9.8 kV 9.8 kV
Up-to-downstream 12.3 kV (*)
contacts open
Phase-to-earth 9.8 kV 9.8 kV
(*) 14.7 kV for front face class II circuit-breaker as per IEC 61 140
een upstream
stream

18. 18
EC 60947-2
Constructional requirements
Circuit-breaker suitable for isolation
Test of isolation suitability
n 3 tests designed to ensure users that a device
«suitable for isolation» is not dangerous
o in open position...
- even after having eliminated a short-circuit up to Icu
- even in the event of overvoltage on the network ...
or in closed position
o cannot be declared «open» and/or « padlockable »

19. 19
EC 60947-2
Constructional requirements
Circuit-breaker suitable for isolation
Leakage current measurement test
at 110 % of maximum utilization voltage Ue
n New device, leakage current < 0.5 mA per pole,
n After breaking at Ics, leakage current < 2 mA per pole,
n After durability tests, leakage current < 2 mA per pole,
n After breaking at Icu, leakage current < 6 mA per pole
Impulse voltage withstand
n Uimp = 12 kV (instead of 9.8 kV) between the inlet and the outlet of the
open device
(*) 14.7 kV for front face class II circuit-breaker as per IEC 61 140
Mechanical ruggedness test
n Circuit-breaker with a pole held in closed position must not be indicated
«open» and/or «lockable» by padlock.
Padlockable in « open » position
Class ll
enclosure
Class ll
front face
class ll
al ruggedness

20. 20
EC 60947-2
Constructional requirements
Circuit-breaker/isolator
Marking
n A circuit-breaker that is «suitable for isolation» will display the circuit-
breaker/isolator symbol on its front face
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21. 21
EC 60947-2
Specific points (appendix A)
n Cascading n Discrimination
Standard IEC 60947-2 recognizes and defines circuit-breaker
co-ordination

22. 22
EC 60947-2
Specific points (appendix B)
Residual current device
Standard IEC 60947-2 appendix B defines
n The characteristics of the residual current devices
n The tests and verifications that must be performed on a residual current
device
o in order to guarantee the safety of the residual current function
o in order to guarantee the quality of the residual current function
(malfunctioning)

23. 23
EC 60947-2
Specific points (appendix B)
Residual current device
Tests and verifications
n Safety of the residual current function
o after breaking at Icu and Ics, no deterioration of the earth leakage
protection units,
o correct operation of the function:
- in harsh environmental conditions
(damp heat 28-day cycle)14h30 duration
(h)

24. 24
EC 60947-2
Specific points (appendix B)
Residual current device
Tests and verifications
n Quality of the residual current function
o no nuisance tripping in the event of:
- single-phase overcurrent (standardized tests)
- current waves generated by impulse voltage
- network capacitance load
- in event of an insulation fault with a DC component
(class A),

25. 25
EC 60947-2
Specific points (appendix F)
Circuit-breaker with electronic trip unit
Standard IEC 60947-2 appendices F defines
n The additional specifications
for circuit-breakers with
electronic trip unit
n The tests required to guarantee
their correct operation in
restrictive industrial
environments
o EMC tests: immunity to
disturbances,
o EMC tests: verification of
radiated emission level,
o (very harsh) environmental
tests, dry and damp heat,
temperature variations
After each test,
verification of proper
trip unit operation
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26. 26
EC 60947-2
Specific points (appendix H)
Circuit-breaker suitable for IT
Standard IEC 60947-2
n Defines this breaking type
(with a single pole at phase-to-phase voltage)
n Stipulates a specific test
o the devices not suitable for use with the IT system are marked
with the symbol IT
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27. 27
EC 60947-2
Tests
Standard IEC 60947-2 makes provision for complete device testing
Cumulative tests grouped into sequences
n One sample undergoes all the sequence tests
5 Test Sequences + 1 Combined test sequence
n All the functions and characteristics are tested
Specific tests
n Circuit-breaker suitable for isolation
n Residual current device,
n Circuit-breaker with electronic trip unit,
EMC Tests
n etc.

28. 28
EC 60947-2
Test sequences
Category A Category B
Icw < Ics Icw = Ics Icw = Ics = Icu
Sequence 1
General operating n n n n
characteristics
Sequence 2
Service breaking n n
capacity Ics
Sequence 3
Ultimate breaking n n n
capacity Icu
Sequence 4
Rated short time n
withstand current Icw
Combined
test sequence n n
Example NS100 to NS630 C801 to C1251 CM1251 Masterpact
+ Multi 9 Masterpact H2-L1 to 3200 N1-H1
Tests

29. 29
EC 60947-2
Example
n Sequence 1 and 2
Test Circuit-breaker type Tests to be performed in turn Additional tests for
sequences Cat. A Cat. B on the same circuit-breaker circuit-breakers declared
Icw Icw Icw suitable for isolation
< Ics = Ics = Ics
= Icu
Sequence 1 1. Verification of tripping thresholds 1. Ditto
General 2. Dielectric properties 2. Dielectric properties
operating 2.1 If an Uimp is declared by the Uimp withstand compulsory:
characteristics Manufacturer: Uimp Test phase-to ditto opposite plus between
n phase, phase-to-earth Inlet and Outlet: Uimp + 25 %
2.2 If no Uimp is declared and leakage current test
Dielectric test 50 Hz at 2Ui + 1000 (< 0.5 mA per pole at 110 % Ue)
3. Mechanical durability 3. Ditto
4. Electrical durability 4. Ditto
5. Operation in overload at 6 In 5. Ditto
6. Dielectric withstand at 2 Ue (min. 1000 V) 6. Ditto + leakage current test
(< 2 mA per pole at 110 % Ue)
7. Temperature rise at In 7. Ditto
8. Verification of non-drift of 8. Ditto
overload trip units
Sequence 2 1. Three successive current breakings Ics 1. Ditto
Service as per cycle O - 3 mm - CO - 3 mm - CO
breaking 2. Verification of suitability for 2. Ditto
capacity Ics n operation, achievement of 5 %
of electrical durability
3. Dielectric withstand at 2 Ue (50 Hz-1 mm) 3. Ditto + leakage test current
(≤2 mA per pole at 110 % Ue)
4. Temperature rise at In 4. Ditto
5. Verification of non-drift of 5. Ditto
overload trip units
Test sequences

30. 30
EC 60947-2
Tests
n Tripping curves
o all the important points
on the tripping curve
are tested
o essential features are tested in real
and the hardest conditions
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31. 31
EC 60947-2
In «sequence 3» of standardized tests
O - t - CO test
Verifications
n Dielectric at 2 Ue (minimum 1000 V) for 1 minute,
NB: for circuit-breaker suitable for isolation
test of leakage I = < 6 mA at 110 % Ue
n Verification of overload trip units at 2 Ir
Standard IEC 60947-2 clarifies the definition of circuit-breaker
breaking capacity
The circuit-breaker must not be «dangerous » after 2 breakings at Icu
Tests Icu

32. 32
EC 60947-2
Tests Ics
In « sequence 2 » of standardized tests
O - t - CO - t - CO test
Verifications
n Dielectric at 2 Ue (minimum 1000 V) for 1 minute,
NB: for circuit-breaker suitable for isolation
test of leakage I ≤2 mA at 110 % Ue
n Of suitability to break its nominal current by achieving 5% of electrical
durability
n Of temperature rise at In,
n Verification of overload trip units at Ir
The circuit-breaker must be suitable for operation after a short circuit
at Ics. This performance is guaranteed 3 times.
The Ics performance represents a « practical » breaking capacity.

33. 33
EC 60947-2
In « sequence 4 » of standardized tests
Category B circuit-breaker
Verifications
n Device withstand at Icw and ∆t indicated by the manufacturer
n Of temperature rise at In, after O - t - CO cycle
at Icw at maximum voltage
n Dielectric at 2 U1(minimum 1000 V) for 1 minute,
n Overload trip units at 2 Ir
The circuit-breaker must be suitable for operation after a short-circuit
at Icw
Tests Icw

34. 34
EC 60947-2
Conclusion
Standard IEC 60947-2
A standard that adheres to reality
Simple, clear choice of circuit-breakers
n In and Icu are sufficient to determine the circuit-breaker,
New recognized, defined and tested characteristics / functions
n Suitability for isolation,
n Residual current device,
n Circuit-breakers with electronic trip unit
Tests representative of the real stresses exerted on a circuit-breaker
n Ics, etc.
n Cumulative tests in sequences,
n Tests of all the design characteristics

35. 35
EC 60947-2
Standard IEC 60947-2
A standard that adheres to reality
Examples
o probable Isc very close to o probable Isc less than
prospective Isc: Ics = 100 % Icu prospective Isc: Ics = 50 % Icu
NS160N is optimized C60L is optimized
Conclusion
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1250 kVA
Isc = 29 kA
28 kA
160 A
MSB
Sub-distribution
board
18 kA
8.5 kA

36. 36
EC 60947-2
Conclusion
A circuit-breaker certified according to Standard IEC 60947-2
guarantees a quality device with durable performance of all its safety
functions.
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